Directed by Clare Kilner. Written by Neena Beber. (PG-13. 101 minutes. At Bay Area theaters.)

Pop princess Mandy Moore lights up the screen in "How to Deal," which is not to say she's great in the movie. She might be adorable and have charisma to burn, but Moore still seems more performer than actress.

She's simply too dynamic, her movements too pronounced, her expressions too vivid. In a scene where her character rakes leaves, Moore seems to be telegraphing moves for invisible backup dancers.

"How to Deal," a thoughtful but uneven teen picture, also has too much going on. A mature-minded follow-up vehicle for Moore after the old-fashioned "A Walk to Remember," "Deal" brings on the calamities. Divorce, marriage, death and teen pregnancy make appearances in the first half. The expected swarm of locusts never arrives, but you know they thought about it.

MORE THAN A CRUSH

Still, the picture is a notch above other teen movies because it takes its teens -- and their parents -- seriously. The romance between Moore's character and a mop-haired charmer (Trent Ford) often takes a backseat to family drama --

a daring approach, if ultimately a detrimental one. Like cinematic ancestor Molly Ringwald in "Sixteen Candles," Moore's Halley has more than a crush to deal with. Thankfully, a talented supporting cast smooths out the more cartoonish developments.

Halley is resistant to the dreamboat's advances after her parents obtain a divorce decree and her sister becomes engaged on the same day. Dad, an outrageous radio DJ played as a sweet doofus by Peter Gallagher, has ditched his wife for a young bimbo. This act seems especially dumb given that Allison Janney, an actress of uncommon dignity and good humor, plays the mother.

Janney (TV's "The West Wing") makes a caring, witty mom, and even brings a wounded grace to her character's man-bashing tirades. She's so likable that the mother's fledgling romance with a Civil War re-enactor (Dylan Baker) competes for interest with the teen relationship.

Not that we see a lot of Moore and Ford together. Director Clare Kilner makes some weird choices. She crams the kids' courtship into a montage, but then draws out a hackneyed scene of Halley's family at dinner with their snooty in-laws.

More of the central pair might have helped the film because Ford's soft good looks and teasing manner put Moore at ease, bringing out a lovely sensuality in the young actress. These moments play to Moore's most appealing trait, which is being innocent without being square.

"How to Deal" often shifts from drama to screwball -- perhaps to keep the kids interested -- then milks its best jokes. Veteran actress Nina Foch ("Executive Suite") brings spaced-out cool to the role of Halley's pot-addled grandma (it's medicinal), but by the time Granny gets the munchies, it's five cannabis quips too many.

NO FREDDIE PRINZE JR.

Yet director Kilner does a fine job elsewhere, especially a scene where Halley and her beau sneak off to a party on the outskirts of town. There's no Freddie Prinze Jr. sheen to this gathering. It's a scuzzy affair, with predatory boys, catty girls and a whiff of danger -- just like real high school parties.

A subplot involving Halley's pregnant best friend benefits greatly from actress Alexandra Holden's warm, clear-eyed performance. Parents should know that while "How to Deal" treats the pregnancy issue with delicacy, drugs and alcohol are almost always played for laughs. It's a curious choice for an otherwise sensitive movie, but not surprising for a picture that's all over the map.